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Hurricaine Flossie Update

With the possibility of  dangerous conditions associated with the Pacific hurricane Flossie, the Gemini Observatory offices in Hilo, Hawaii and the facilities on Mauna Kea will be closed on Monday night and Tuesday (day and night).

For more information on the current status of the storm see the Central Pacific Hurricane Center: http://www.prh.noaa.gov/cphc/tcpages/FLOSSIE.php

Updates will be provided here as circumstances require and allow.

NIR Detector

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The NIRI near-IR science detector is a 1024x1024 Aladdin InSb array with 27 micron pixels and sensitive from ~1 to 5 microns made by Raytheon/Santa Barbara Research Center. The camera lenses focus the telescope beam onto the detector with precise focussing being achieved by a translational focus stage upon which the array is mounted. The photo below shows the Aladdin array mounted on this focus stage.

f/14 Optics

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f/6 Optics

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The f/6 camera optics provides NIRI with a wide-field imaging mode at a pixel scale of 0.116"/pixel and a fov of ~2'. The f/6 camera lens is a multi-component (4) lens of diameter ~80mm made of BaF2, ZnSe, LiF and ZnS. All but two surfaces are spherical with one ZnSe and ZnS surface being aspheric. The top of the wide-field f/6 lens can be

f/32 Optics

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Pupil Viewer Optics

NIRI Optical Overview - Pupil Viewer Optics

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Beam Steerer

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Pupil Mask/Filter Wheel

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The pupil mask/filter wheel is of a similar design as the two filter wheels, is 530mm in diameter and contains apertures for up to 12 masks and filters. The nominal pupil image has a diameter of 36mm. In fact, this is where the 5 NIRI grisms (transmission grating prisms) are located to facilitate observations in its spectroscopic mode.

Collimator Lens

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The NIRI collimator lens is a two element lens made of LiF and BaF2. The first lens are both spherical with the first being a meniscus while the second is plano-convex. They both have a diameter of ~55mm. It is located between the two filter wheels on the science path optical table. Below are two photos of the collimator unit without the filters wheels mounted on the table.

Filter Wheels

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The NIRI filter wheels are 530mm in diameter and each contains 12 apertures for mounting near-IR filter. Filter wheel #1 is located immediately after the two fold mirrors and is in the uncollimated telescope beam. This filter wheel will hold broad band near-IR filters i.e. those not as sensitive to the collimated nature of the incident radiation. Filter wheel #2 is located after the collimator lens in the collimated beam and will hold narrow band near-IR filters